Centrifugal fan and method

ABSTRACT

An impeller, fan assembly, and associated methods are shown. Selected configurations are shown that include a circumferential feature formed within a plate of an impeller and spaced apart from edges of the plate.

TECHNICAL FIELD

Embodiments described herein generally relate to fan assemblies. Specific examples may include plenum or plug fan housings and fan assemblies and centrifugal fan assemblies.

BACKGROUND

Fan impellers are routinely subjected to large forces such as centrifugal forces during operation. These forces may eventually lead to unwanted cracking or fatigue failure in one or more components of the impeller. Improved configuration and methods are desired to improve strength and reliability of impellers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an orthogonal view of a fan assembly in accordance with some embodiments of the invention.

FIG. 2A is a cross section view of a fan impeller of the prior art.

FIG. 2B is a cross section view of a fan impeller in accordance with some embodiments of the invention.

FIG. 3 is a flow diagram of a method of making a fan impeller in accordance with some embodiments of the invention.

DESCRIPTION OF EMBODIMENTS

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

FIG. 1 shows a fan assembly 100 according to one example. The fan assembly 100 includes a motor 110, a support fame 140 holding the motor in place, and an impeller 120. In FIG. 1, the impeller 120 is coupled directly to a shaft of the motor 110, although the invention is not so limited. In other examples, the impeller 120 is coupled to a shaft of the motor 110 indirectly through a belt drive, or other transmission such as a gear box, etc. A front plate 130 is further shown in FIG. 1 as part of the fan assembly 100, and a funnel 132 is used to direct air into the impeller 120.

The impeller 120 shown in FIG. 1 is configured as a centrifugal impeller, having a back plate 122, a front plate 124, and a number of blades 126 coupled between the front plate 124 and the back plate 122. Blades 126 may include single thickness metal flat blades, curved blades, airfoil shaped blades, or other suitable blade shapes.

The fan assembly 100 shown may be used in a number of different configurations, including but not limited to a turbine or plenum fan. The impeller 120 as described in more detail below may be used in any number of different fan configurations. The fan assembly 100 shown in FIG. 1 is merely one example for illustration.

FIG. 2A shows a centrifugal impeller 200 according to the prior art. The centrifugal impeller 200 is shown as half a cross section, with a center of the impeller 200 at location 201. The centrifugal impeller 200 is shown with a back plate 222, a front plate 224, and one representative blade 226 of a number of blades. Centrifugal impellers are often subjected to high cyclic stresses that can cause cracking and eventual failure in one or more of the plates. In the configuration of impeller 200, a reinforcing ring 228 is welded onto the front plate 224. An amount of weld material 230 is shown at the interface between the front plate 224 and the reinforcing ring 228.

A welding operation to attach the reinforcing ring 228 may be expensive, and the heat of welding may weaken the plate material and/or introduce unwanted stress concentration features, such as notches or other imperfections from the weld material 230. Additionally, it may be difficult to center the reinforcing ring 228 on the front plate 224, which may lead to an unwanted imbalance in the impeller 200.

FIG. 2B shows a centrifugal impeller 120 according to an example of the present invention. Similar to FIG. 2A, the centrifugal impeller 120 is shown as half a cross section, with a center of the impeller 120 at location 121. The centrifugal impeller 120 is shown with a back plate 122, a front plate 124, and one representative blade 126 of a number of blades. A circumferential feature 128 is shown formed within the front plate 124, and spaced apart from an outside edge 152 and an inside edge 154. The circumferential feature 128 extends outward in a direction normal to a plane of the front plate 124. The circumferential feature 128 shown in FIG. 2B extends outward to the left of the front plate 124, however in other examples, the circumferential feature 128 may extend outward to the right, toward the back plate 122.

The process of forming the circumferential feature 128 provides a number of advantages, both for manufacturability, and physical property advantages. For manufacturability, the process or forming the circumferential feature 128 is less time consuming than welding an additional reinforcing ring 228 onto the front plate, as shown in FIG. 2A. With regard to physical properties, when the circumferential feature 128 is formed, the metal becomes work hardened in and around the circumferential feature 128, providing increased strength. The work hardening comes from microstructural difference in the material that are caused by the forming process.

In one example, the location of the circumferential feature 128, in between and spaced apart from the outside edge 152 and the inside edge 154, provides a strengthening property to the front plate 124 at a location apart from the edges 152 and 154 that may be prone to failure. The addition of the circumferential feature 128 may reduce or eliminate a likelihood of failure.

Although the circumferential feature 128 is shown formed between and spaced apart from the outside edge 152 and the inside edge 154, the invention is not so limited. In one example, a circumferential feature is formed on the back plate 122, between and spaced apart from an outside edge 125 and the center 121. In one example a circumferential feature as described is formed in both a front plate 124 and a back plate 122. Although a single circumferential feature is shown within the front plate, in other examples multiple circumferential features may be formed for additional strengthening between and spaced apart from the outside edge 152 and the inside edge 154. Multiple circumferential features may also be formed within the back plate 122 in selected examples.

In addition to the formed circumferential feature 128, in selected examples an outer edge feature and/or an inner edge feature may be formed at the outside edge 152 and/or the inside edge 154. Such additional features may further enhance strengthening of the plates, such as the front plate 124 and the back plate 122, without the need for welding additional components onto the plates.

In the example shown, the circumferential feature 128 shows a semi-circular cross section. Other geometries for a cross section of the circumferential feature 128 are also possible, including, but not limited to angled or V shaped cross sections, box cross sections, or other suitable cross sections.

One suitable material for all or a portion of the impeller 120 includes aluminum or an aluminum alloy. Another suitable material for all or a portion of the impeller 120 includes steel. Other formable metallic materials are also within the scope of the invention.

FIG. 3 shows a flow diagram of one method of forming a fan assembly according to an embodiment of the invention. In operation 302, a number of fan blades are attached, extending substantially normal at a periphery of a first circular plate. In operation 304, a circumferential feature is formed within a second circular plate and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate. In one example, attaching the fan blades includes welding the fan blades.

As discussed above, the process of forming the circumferential feature provides a number of advantages, including simplifying manufacture, and providing increased strength. In one example, forming the circumferential feature includes pressing, the circumferential feature into a side of a plate using a die and a press, such as a hydraulic press. In this operation, the entire circumferential feature may be formed in one stroke of the press, which may speed up manufacture.

In one example, the circumferential feature may be spin formed into the plate. Spin forming provides an advantage of ensuring that the circumferential feature is centered about an axis of rotation of the plate, and/or the impeller as assembled. In one example, spin forming includes pressing the plate over a mandrel or die as the mandrel or die is being rotated.

In operation 306, the second circular plate is attached to the number of fan blades in a location opposite and substantially parallel to the first circular plate. In one example, attaching the second circular plate includes welding the second circular plate to the fan blades.

To better illustrate the method and apparatuses disclosed herein, a non-limiting list of examples is provided here:

Example 1 includes a centrifugal fan impeller. The impeller includes a number of circular plates, including a back plate, and a ring shaped front plate, a number of blades coupled between the back plate and the front plate, and a circumferential feature formed within at least one of the plates and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate.

Example 2 includes the centrifugal fan impeller of example 1, wherein the circumferential feature has a semi-circular cross section.

Example 3 includes the centrifugal fan impeller of any one of examples 1-2, wherein the circumferential feature has an angled cross section.

Example 4 includes the centrifugal fan impeller of any one of examples 1-3, wherein the components are formed from steel.

Example 5 includes the centrifugal fan impeller of any one of examples 1-4, wherein the components are formed from aluminum.

Example 6 includes the centrifugal fan impeller of any one of examples 1-5, further including an outer edge formed feature in one or more of the number of circular plates.

Example 7 includes the centrifugal fan impeller of any one of examples 1-6, further including an inner edge formed feature in one or more of the number of circular plates.

Example 8 includes the centrifugal fan impeller of any one of examples 1-7, wherein the number of blades includes airfoil blades.

Example 9 includes the centrifugal fan impeller of any one of examples 1-8, wherein the number of blades includes single thickness blades.

Example 10 includes a fan assembly, including a motor and an impeller coupled to a shaft of the motor. The impeller includes a number of circular plates, including a back plate, and a ring shaped front plate, a number of blades coupled between the back plate and the front plate, a circumferential feature formed within at least one of the plates and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate, and a support frame coupled to the motor.

Example 11 includes the fan assembly of example 10, wherein the shaft of the motor is directly coupled to the impeller.

Example 12 includes the fan assembly of any one of examples 10-11, wherein the impeller is coupled to the shaft of the motor using a drive belt.

Example 13 includes the fan assembly of any one of examples 10-12, wherein the fan assembly is configured as a plenum fan.

Example 14 is a method including attaching a number of fan blades extending substantially normal at periphery of a first circular plate, forming a circumferential feature within a second circular plate and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate, and attaching the second circular plate to the number of fan blades in a location opposite and substantially parallel to the first circular plate.

Example 15 includes the method of example 14, further including forming a circumferential feature within the first circular plate and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate.

Example 16 includes the method of any one of examples 14-15, wherein forming a circumferential feature includes forming a semi-circular cross sectioned feature.

Example 17 includes the method of any one of examples 14-16, wherein forming a circumferential feature includes forming multiple circumferential features in a single plate, the multiple features spaced apart from edges of the plate, the multiple features extending outward in a direction normal to a plane of the plate.

Example 18 includes the method of any one of examples 14-17, wherein forming a circumferential feature includes spin forming.

Example 19 includes the method of any one of examples 14-18, wherein forming a circumferential feature includes pressing.

The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. 

1. A centrifugal fan impeller, comprising: a number of circular plates, including a back plate, and a ring shaped front plate; a number of blades coupled between the back plate and the front plate; and a circumferential feature formed within at least one of the plates and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate.
 2. The centrifugal fan impeller of claim 1, wherein the circumferential feature has a semi-circular cross section.
 3. The centrifugal fan impeller of claim 1, wherein the circumferential feature has an angled cross section.
 4. The centrifugal fan impeller of claim 1, wherein the components are formed from steel.
 5. The centrifugal fan impeller of claim 1, wherein the components are formed from aluminum.
 6. The centrifugal fan impeller of claim 1, further including an outer edge formed feature in one or more of the number of circular plates.
 7. The centrifugal fan impeller of claim 1, further including an inner edge formed feature in one or more of the number of circular plates.
 8. The centrifugal fan impeller of claim 1, wherein the number of blades includes airfoil blades.
 9. The centrifugal fan impeller of claim 1, wherein the number of blades includes single thickness blades.
 10. A fan assembly, comprising: a motor; an impeller coupled to a shaft of the motor, including: a number of circular plates, including a back plate, and a ring shaped front plate; a number of blades coupled between the back plate and the front plate; a circumferential feature formed within at least one of the plates and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate; and a support frame coupled to the motor.
 11. The fan assembly of claim 10, wherein the shaft of the motor is directly coupled to the impeller.
 12. The fan assembly of claim 10, wherein the impeller is coupled to the shaft of the motor using a drive belt.
 13. The fan assembly of claim 10, wherein the fan assembly is configured as a plenum fan.
 14. A method, comprising: attaching a number of fan blades extending substantially normal at periphery of a first circular plate; forming a circumferential feature within a second circular plate and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate; and attaching the second circular plate to the number of fan blades in a location opposite and substantially parallel to the first circular plate.
 15. The method of claim 14, further including forming a circumferential feature within the first circular plate and spaced apart from edges of the plate, the feature extending outward in a direction normal to a plane of the plate.
 16. The method of claim 14, wherein forming a circumferential feature includes forming a semi-circular cross sectioned feature.
 17. The method of claim 14, wherein forming a circumferential feature includes forming multiple circumferential features in a single plate, the multiple features spaced apart from edges of the plate, the multiple features extending outward in a direction normal to a plane of the plate.
 18. The method of claim 14, wherein forming a circumferential feature includes spin forming.
 19. The method of claim 14, wherein forming a circumferential feature includes pressing. 